Choanocytes (also known as "collar cells") are cells that line the interior body walls of sponges that contain a central flagellum surrounded by a collar of microvilli. It is the closest family member to the free-living ancestor called choanoflagellate. The flagellum beats regularly, creating a water flow across the microvilli which can then filter nutrients and other food from the water taken from the collar of the sponge. Food particles are then phagocytosed by the cell. Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell. Cells in culture, stained for keratin (red) and DNA (green). ... This article is about the animal. ... A flagellum (plural, flagella) is a whip-like organelle that many unicellular organisms, and some multicellular ones, use to move about. ... Categories: Stub ... The choanoflagellates are a group of flagellate protozoa. ... Filter feeders (also known as suspension feeders) are animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized structure, such as the baleen of baleen whales. ...

By lining the walls of spongocoel, they create an intracellular space called the porocyte. A spongocoel is the large, central cavity of the animals in Phylum Porifera. ...